The present invention is directed to an absorbent product having at least a top layer, an absorbent core, and a breathable outer cover. A hydrophobic foam dampness-inhibiting layer is disposed directly beneath the breathable outer cover, thereby maintaining an air space within the foam layer. The air space causes a reduction in perceived surface dampness on the outer surface of the breathable outer cover when the absorbent core is wet.
Absorbent articles, such as diapers, child training pants, adult incontinence garments, swim wear and the like, typically include at least a liquid-permeable top layer for direct contact with the wearer, an absorbent core layer, and a substantially liquid-impermeable outer cover. The absorbent core is positioned between the top layer and the outer cover. When the absorbent article is exposed to a liquid insult, liquid passes through the top layer and into the absorbent core. The outer cover prevents the liquid in the absorbent core from leaving the garment.
Many of today""s absorbent garments utilize breathable outer cover materials. Breathable outer cover materials are substantially impermeable to liquids, but are permeable to water vapor. Breathable outer cover materials permit escape of water vapor from the absorbent garment, increasing the garment comfort and reducing skin rashes and other irritations that result when water vapor is maintained inside the garment and heated by the wearer""s body. Many of today""s absorbent garments are highly breathable, for maximum wearer comfort.
One shortcoming of breathable absorbent articles is a cold, damp, clammy feel that often occurs on the outside of the garment, i.e., on the outside of the outer cover. As liquid water in the absorbent core evaporates and passes through the microporous outer cover material, the associated evaporative cooling causes a lowering of temperature of the absorbent core and the adjacent outer cover material, resulting in a clammy, damp-feeling outer cover. The high moisture flux through the outer cover also causes the air in the vicinity of the outer cover surface to be at or near saturation. Humid air has a higher thermal conductivity than dry air, which the fingers can sense, further exacerbating perceptions of dampness.
There is thus a need or desire in the absorbent garment industry for absorbent articles which are highly breathable, yet which reduce or avoid the perceived dampness caused by evaporative cooling.
The present invention is directed to an absorbent article having a breathable outer cover and reduced perceived outer cover dampness. The absorbent article includes at least a liquid-permeable top layer, a breathable, substantially liquid impermeable outer cover, and an absorbent core layer between the top layer and the outer cover. In accordance with the invention, a hydrophobic foam dampness-inhibiting layer is interposed between the absorbent core and the breathable outer cover. This hydrophobic foam layer maintains air within the foam, thereby providing several beneficial functions to the diaper.
One benefit provided by the foam dampness-inhibiting layer is that the air space insulates the absorbent core from the outer cover and slows heat transfer from a person""s fingers touching the outer surface of the outer cover to the diaper, causing the diaper to feel less clammy or cold. Another benefit is that the air space in combination with the foam layer provides a resilient, soft, springy surface to the fingers, giving an aesthetic improvement over feeling just wet gel beneath the outer cover in the absence of the foam layer. In theory, the air space also allows pathways for side diffusion and convection, speeding the removal of moisture from the diaper, especially moisture near the skin. This increased removal of moisture contributes to reduced, therefore improved, skin hydration. Furthermore, the air space separates the wet absorbent core of super-absorbent material, gel or pulp, from resting against the inside surface of the outer cover material, thereby allowing for a much greater surface area in which water molecules may migrate across the gel/air interface. Finally, this invention teaches a foam dampness-inhibiting layer that is permeable enough to not occlude moisture from leaving the diaper in any appreciable amount.
With the foregoing in mind, it is a feature and advantage of the invention to provide an absorbent article having a breathable outer cover in combination with a hydrophobic foam dampness-inhibiting layer that slows heat transfer from the fingers touching the outer cover to an absorbent core, thus reducing clamminess and coolness felt at the outer cover compared to prior art absorbent articles.
It is a further feature and advantage of the invention to provide an absorbent garment from which moisture is readily removed, thereby resulting in reduced skin hydration.
It is also a feature and advantage of the invention to provide an absorbent article having a resilient, soft, springy surface feel.
It is also a feature and advantage of the invention to provide diapers, child training pants, adult incontinence garments, swim wear, and other (e.g. medical) absorbent products which embody the features of the improved absorbent article of the invention.